The FBI has released a video showing the detonation of a prototype of the failed car bomb that was supposed to go off in Times Square in May.
Had the device been made correctly, FBI officials say, it would have killed dozens of people and caused 'devastating' damage.
Faisal Shahzad, who has admitted to planting the car bomb in a parked SUV on May 1, told investigators that he believed it would have killed about 40 people.
In the video released by the FBI, the Operational Technology Division sets up tests in a field in Osceola Mills, Pennsylvania, on June 29.

The explosive tests involve a 1993 Nissan Pathfinder stuffed with 250 pounds of ammonium nitrate and diesel fuel, along with three 25-pound propane tanks and two five-gallon gasoline containers.

Taken from various angles, using normal and slow-motion cameras, the FBI video reveals that the explosion would have been quite large - almost certainly enough to kill scores of people in crowded Times Square.

In a memorandum urging a federal judge to sentence Shahzad to life in prison, prosecutors today said Shahzad told the FBI that - had the Times Square bomb been successful - he planned to build and set off another car bomb somewhere in New York City two weeks later.

'While it is impossible to calculate precisely the impact of Shahzad's bomb had it detonated, the controlled detonation... demonstrated that those effects would be devastating to the surrounding area,' the sentencing document said.

Shahzad is set to be sentenced next week.

Prosecutors told the court today: 'Shahzad used the Internet to access websites that provided real time video feeds of different areas of Times Square.
'According to Shahzad, he wanted to select the busiest time for pedestrian traffic in Times Square because pedestrians walking on the streets would be easier to kill and to injure than people driving in cars.'
Shahzad was arrested on May 3, two days after the unexploded bomb was discovered in Times Square.
Shahzad, a former U.S.-educated financial analyst, pleaded guilty after confessin